The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

Both of us, you and I, began as single cells. Our genes are different, albeit marginally. The way our bodies develop are different. Our skin, our hair, our bones, our brains are all built differently. Our life experiences vary widely. I lost two uncles to mental illness. I lost a father to a deadly spiral following a fall. A knee to arthritis. A friend—so many friends—to cancer. And yet, despite all the yawning gaps between our bodies and experiences, you and I share two features. First, we arose from a single-celled embryo. And second, from that cell came multiple cells—those that populate your body and mine. We are built of the same material units and are akin to two different nuggets of matter built from the same atoms. What are we made of? Some ancients believed that we were created by menstrual blood that had congealed into bodies. Some believed we came preformed: mini-beings that just expanded over time, like human-shaped balloons blown up for a parade. Some thought humans were sculpted from mud and river water. Some thought we transformed gradually in the womb from tadpole-like beings to fish-mouthed creatures, and, finally, into humans. But if you looked down a microscope at your skin and mine, or your liver and mine, you would find them strikingly alike. And you’d realize that all of us were, in fact, built out of living units: cells. The first cell gave rise to more cells, and then divided to form even more, until our livers and guts and brains—all the elaborate ...